JPH09151147A - Separation of xylenol isomer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate and obtain 2,4-xylenol as a strong adsorptive component on the extract side by separately adsorbing from a mixture of alkylphenol isomers using a specific adsorbent. SOLUTION: This separation is carried out by mixing a mixture of alkylphenol isomers containing 2,4-xylenol with an adsorbent comprising zeolite, adsorbing a strong adsorptive component, while selectively leaving a weak adsorptive component, and then selectively adsorbing the strong adsorptive component by further mixing a raffinate abunsantly containing the weak adsorptive component with the adsorbent. As a result, a high purity weak adsorptive component is provided in the raffinate. On the other hand, on the adsorbed side, 2,4-xylenol is obtained as the extract component accompanying a desorption agent by desorbing the adsorbed component with a desorption agent. Zeolite containing strontium and/or cupper is preferable. Among zeolites, faujasite type (X type is especially suitable) and beta type are preferable.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for separating 2,4-xylenol from an alkylphenol isomer mixture by adsorption separation treatment.

[0002]

2. Description of the Related Art An adsorption separation technique using a zeolite adsorbent is known as a separation technique for such an alkylphenol isomer mixture. For example, a method of adsorbing and separating xylenol from a mixture of cresol and xylenol is disclosed in Japanese Patent Publication No. 58-13527, 2,6-xylenol and m-cresol, and 2,6-di-tert-butyl-4-methylphenol. Phenol, or α-naphthol and o
-Adsorption and separation of cresol is described in JP-B-58-58330, and from a mixture containing xylenol isomers, 3,5
-A method for recovering xylenol by adsorption separation is disclosed in JP-B-59-122433 and JP-A-3-20234.
No., published in Japanese Unexamined Patent Publication No.

[0003]

Among various alkylphenols, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, p-ethylphenol and m-ethylphenol have similar boiling points, and ordinary distillation or the like is required. It is very difficult to separate by means of. Among these, 2,4-xylenol is a compound useful as a raw material for pressure-sensitive heat-sensitive dyes, pigments and insecticides. 2,4
Regarding the separation of xylenol, JP-A-3-20234 discloses a process of separating a xylenol isomer mixture into an extract containing 2,5-xylenol and a raffinate containing 2,4-xylenol.
No mention is made of a method for purifying 2,4-xylenol in one step, and an efficient separation method is desired.

[0004]

Means for Solving the Problems The inventors of the present invention have earnestly studied a method for efficiently separating 2,4-xylenol from an alkylphenol isomer mixture by using an adsorbent containing zeolite, and the adsorbent containing zeolite. 2,4-xylenol as a strongly adsorbing component on the extract side by adsorption separation using 2,4-xylenol
It was found that the separation efficiency of xylenol was improved, and the present invention was achieved. That is, the present invention is characterized by separating 2,4-xylenol as an extract from an alkylphenol isomer mixture containing 2,4-xylenol using an adsorbent containing zeolite and a desorbent. -A method for separating xylenol.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The alkylphenol isomer mixture used for separation in the present invention is an alkylphenol mixture containing 2,4-xylenol, and 2,5-xylenol, 2,3-xylenol, p- It is particularly effective in separating 2,4-xylenol from a mixture containing ethylphenol and m-ethylphenol. .

The zeolite contained in the adsorbent used in the present invention may be any one of faujasite type, beta type, pentasil type and the like. Preferred examples include faujasite type and beta type. For example, faujasite-type zeolite is a crystalline aluminosilicate represented by the following formula.

0.9 ± 0.2 M _{2 / n} O: Al ₂ O ₃ : xS
iO ₂ : yH ₂ O Here, M represents a cation, and n represents its valence.

Faujasite-type zeolite is produced in a form having sodium as a cation, and the cation can be easily exchanged by ion exchange. Ion exchange methods for cations are widely known to those skilled in the art having knowledge of the production of crystalline aluminosilicates and usually involve adding the zeolite to an aqueous solution of a soluble salt of one or more cations to be added to the zeolite. Can be carried out by contacting. This contact may be repeated several times as necessary. In the present invention, it is preferable to contain strontium ions or copper ions, and the ion exchange is carried out using an aqueous solution of these salts, for example, strontium nitrate, strontium chloride, strontium bromide, copper nitrate, copper chloride, copper bromide and the like. be able to. Ion exchange can be performed for other zeolites by the same method.

The technique for adsorptive separation of an alkylphenol mixture using the method of the present invention may be a so-called chromatographic preparative method, or an adsorbing separation method using a continuous simulated moving bed.

The continuous adsorption / separation technique using a simulated moving bed is basically carried out by continuously circulating the following adsorption operation, concentration operation and desorption operation.

(1) Adsorption operation: The alkylphenol mixture is brought into contact with the adsorbent containing zeolite, and the strong adsorption component is adsorbed while selectively leaving the weak adsorption component. The strongly adsorbed component is recovered as an extract component together with a desorbing agent described later.

(2) Concentration operation: Raffinate containing a large amount of weakly adsorbed components is further brought into contact with an adsorbent to selectively adsorb strongly adsorbed components, whereby the weakly adsorbed components in the raffinate are highly purified.

(3) Desorption operation: The highly purified weakly adsorbed component is recovered together with the raffinate, while the adsorbed component is expelled from the adsorbent by the desorbent and is recovered as an extract component together with the desorbent.

As operating conditions for adsorption and separation, the temperature is room temperature to 350 ° C., preferably 50 to 250 ° C., and the pressure is atmospheric pressure to 5 MPa, preferably atmospheric pressure to 4 MPa. The adsorption separation according to the invention may be in the gas phase or in the liquid phase, but is preferably carried out in the liquid phase in order to reduce the operating temperature and to suppress undesired side reactions of the raw material feed or the desorbent. The desorbent used in the present invention may be essentially any compound having a boiling point different from that of the alkylphenol compound used for the separation. Preference is given to alcohols and ethers, more preferably aliphatic alcohols and aromatic ethers. In the adsorptive separation in the present invention, the larger the carbon number of the desorbent, the weaker the desorption force becomes, and the more practical the desorbent becomes.
Therefore, the desorbent having 1 to 12 carbon atoms is preferably used. The structure of the desorbent may be linear or branched, but a linear one that is more stable under the adsorption separation condition is preferable. Specifically, 1-butanol, 1-pentanol, 1-hexanol, anisole and the like are particularly preferably used.

[0015]

Next, the method of the present invention will be described with reference to examples.

In the examples, the adsorption characteristics of the adsorbent are expressed by the following equation (1)
Is represented by the adsorption selectivity (α).

(Equation 1) Here, A and B represent any one of alkylphenol isomers, S represents an adsorption phase, and L represents a liquid phase in equilibrium with the adsorption phase.

When the value of the above equation is greater than 1, the A component is selectively adsorbed, and when it is less than 1, the B component is selectively adsorbed. Further, the adsorbent having an α value of greater than 1 in the above formula (or an adsorbent smaller than 1 and close to 0) facilitates the adsorption and separation of A and B.

[0018]

【Example】

(Preparation of adsorbent) KY adsorbent As a zeolite powder serving as an adsorbent, a sodium-type Y-type zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 5.5 manufactured by Tosoh Corporation was used. The zeolite powder was molded with 15 parts of alumina in an absolute dry weight ratio of 10
about 8 g in 30 g of 10 wt% potassium nitrate aqueous solution.
Soak at 5 ° C. for about 1 hour. After repeating this operation 7 times,
It was immersed in about 100 g of purified water at the same temperature for about 30 minutes. This operation was also repeated 7 times for ion exchange. This adsorbent was dried at 120 ° C. for about 12 hours to obtain a KY adsorbent.

Sr-X Adsorbent The zeolite powder used as an adsorbent is a Tosoh Corporation SiO ₂ / Al ₂ O ₃ molar ratio =
2.5 sodium type X zeolite was used. The zeolite powder was molded with 20 parts bentonite in an absolutely dry weight ratio, and 10 g of the zeolite powder was immersed in a 10 wt% strontium nitrate aqueous solution at about 85 ° C. for about 1 hour. After repeating this operation 7 times, it was immersed in about 100 g of purified water at the same temperature for about 30 minutes. This operation was also repeated 7 times for ion exchange. This adsorbent was dried at 120 ° C. for about 12 hours to obtain a Sr-X adsorbent.

Cu-X Adsorbent In the Sr-X adsorbent preparation method, the Cu-X adsorbent was prepared in the same manner except that the strontium nitrate aqueous solution was replaced with the copper nitrate aqueous solution.

Sr-beta adsorbent US Pat. No. 3,30
SiO ₂ / Al ₂ O synthesized according to the specification of No. 8,069
Sodium-type beta-zeolite powder with a molar ratio of ₃ = 19.1 was molded with 15 parts of alumina binder by absolute dry weight. About 10 g of the 1N sodium hydroxide aqueous solution about 2
After being dipped in 0 g, it was dipped in 30 g of a 5 wt% copper nitrate aqueous solution at 85 ° C. for about 1 hour. This operation was repeated seven times.
Then, put in 100 g of purified water, and for 30 minutes, 85
The operation of maintaining the temperature at ℃ and washing with water was repeated 7 times. This adsorbent was dried at 120 ° C. for about 12 hours to obtain a Sr-beta adsorbent.

Examples 1 to 3 After calcining at 500 ° C. for 3 hours, the mixture was allowed to cool in a desiccator, about 1.6 g of Sr-X adsorbent and about 2.0 of liquid phase mixture.
5 g was charged in a 5 ml autoclave and contacted for 1 hour. The adsorption experiment was carried out using three kinds of desorbents. The temperature of the adsorption experiment varied depending on the desorbent, and in the case of 1-butanol, 1-pentanol and 1-hexanol, the experiments were conducted at 115 ° C, 135 ° C and 150 ° C, respectively. The composition ratio of the charged liquid phase mixture was alkylphenol isomer mixture: desorbent: t-decalin = 2: 2: 1 (weight ratio). t-decalin was added as an internal standard substance in gas chromatography analysis, and is a substance substantially inactive to the adsorbent in the above experimental results. The composition of the liquid phase mixture after being contacted with the adsorbent was analyzed, and the adsorption selectivity α was determined using the above formula (1). The composition of the alkylphenol isomer mixture used here is 2,4-xylenol:
2,5-xylenol: m-ethylphenol = 52.7:
It was 47.0: 0.30 (weight ratio). The results of using various alcohols as desorbents are shown in Table 1. Compared with the comparative example, it can be seen that in the present invention, 2,4-xylenol is a strongly adsorbed component, the separation coefficient from other components is dramatically increased, and the system is excellent in the separation of 2,4-xylenol. .

Example 4 A Cu-X adsorbent was used in place of the Sr-X adsorbent used in Example 1, 1-butanol was used as the desorbent, and 2,4-xylenol was used as the alkylphenol isomer mixture:
2,5-xylenol: 2,3-xylenol: p-ethylphenol: m-ethylphenol = 52.6: 46.8:
An adsorption experiment was performed under the same conditions as in Example 1 except that a mixture having a composition of 0.30: 0.10: 0.20 (weight ratio) was used. Table 2 shows the results. It can be seen that, out of the five components, 2,4-xylenol is the strongest adsorbing component, and 2,4-xylenol can be isolated in a single step.

[0024]

[Table 1]

[0025]

[Table 2]

Examples 5 to 6 The composition of the alkylphenol isomer mixture used in Example 1 was 2,4-xylenol: 2,5-xylenol = 5.
An adsorption experiment was conducted under the same conditions as in Examples 1 to 3 except that an ether compound was used as a desorbent instead of 3.0: 47.0 (weight ratio). Table 3 shows the results.

Example 7 An adsorption experiment was conducted using 1-pentanol as a desorbent instead of the Sr-X adsorbent used in Examples 1 to 3 instead of the Sr-beta adsorbent. Table 3 shows the results.

[0028]

[Table 3]

Example 8 The Sr-X adsorbent used in Example 1 was packed in a stainless steel column having a length of 1 m and an inner diameter of 4.75 mm, and 1-pentanol as a desorbent was placed in an oil bath at 135 ° C. The flow rate was about 1.8 ml / min. Separated raw material 2,4-xylenol: 2,5-xylenol: 1-pentanol: t-
About 1.6 ml of an isomer mixture consisting of decalin = 2: 2: 4: 2 (weight ratio) was introduced into the column inlet. T-decalin is used as a measure of efflux time and its adsorption is virtually negligible compared to other components. The liquid flowing out of the column outlet was analyzed by a gas chromatograph at every flow time to obtain a flow curve shown in FIG.

[0030]

Industrial Applicability According to the present invention, it becomes possible to separate and collect 2,4-xylenol from an alkylphenol isomer mixture in a high purity with a high yield.

[Brief description of the drawings]

FIG. 1 is a diagram showing a change over time in an outflow amount of each component in Example 8 of the present invention.

Claims (8)

[Claims] 1. A method for separating 2,4-xylenol as an extract from an alkylphenol isomer mixture containing 2,4-xylenol using an adsorbent containing zeolite and a desorbent. Method for separating xylenol. 2. The zeolite is strontium and / or
Or 2, containing copper
Method for separating 4-xylenol. 3. The method for separating 2,4-xylenol according to claim 1, wherein the zeolite is a faujasite type or a beta type. 4. The method for separating 2,4-xylenol according to claim 3, wherein the faujasite-type zeolite is X-type. 5. An alkylphenol isomer mixture comprising:
In addition to 2,4-xylenol, 2,5-xylenol,
2,3-xylenol, p-ethylphenol and m
-2,4- according to any one of claims 1 to 4, characterized in that it is an alkylphenol mixture containing at least one compound selected from ethylphenol.
Method for separating xylenol. 6. The method for separating 2,4-xylenol according to claim 1, wherein the desorbent is alcohol and / or ether. 7. Desorbing agent is characterized in that it is an aliphatic alcohol and / or an aromatic ether.
The method for separating 2,4-xylenol described. 8. The method for separating 2,4-xylenol according to claim 7, wherein the desorbent is an aliphatic alcohol having 1 to 12 carbon atoms and / or an aromatic ether having 7 to 12 carbon atoms. .